I'm a big Evangelion fan, and I'm not sure if I'd want to see a remake of this that's animated. Personally, I think it's perfect the way it is. I'm talking about NGE 1995 and EoE which most consider to be part of the same canon.

It all connects even into the rebuild series, i have to read the manga to be sure but EoE might be completely different or looped as for rebuild i'm pretty sure that's a completely different ball game possibly a what if things went this way instead of that way.

I'm a big Evangelion fan, and I'm not sure if I'd want to see a remake of this that's animated. Personally, I think it's perfect the way it is. I'm talking about NGE 1995 and EoE which most consider to be part of the same canon.

It all connects even into the rebuild series, i have to read the manga to be sure but EoE might be completely different or looped as for rebuild i'm pretty sure that's a completely different ball game possibly a what if things went this way instead of that way.

Well one can speculate, but until the last movie is out we won't know for sure. Also, I didn't really care for the rebuilds. There's just so many problems, but that's for a different thread, I'm sure.

Ya know, sometimes I wonder if remaking some things is really a good idea. I mean... Sailor Moon Crystal probably would've been great if it were released 20 years ago in place of the original, but today... let's just say sometimes the world moves on, and we gotta leave the past in the past. But then, I guess there's the adaptions that sucked so hard, nothing short of a post-apocalyptic rebuilding has a hope of redeeming them.

So the oldest stuff I've seen that I think would still be good today? Uh... Record of Lodoss War?

The modern stuff that needs to be nuked and rebuilt? Haruhi season 2.

And now that I've had time to think about this: Go back in time and change history, remaking a series by replacing what aired with another version?

From the top of my head, definitely Mobile Suit Gundam F91 as a full-fledged TV series (with at least 24 episodes). I feel that the story had lots of potential, but was ruined by being turned into a 2-hour movie.

Those are the two big ones: both brilliant manga that were absolutely destroyed by their adaptations.

Other manga-to-anime adaptations I was disappointed by include:
Ai Yori Aoshi (too much focus on the harem, not enough on the background of the main couple, ruined the ending)
Love Hina (ruined the ending, added an unnecessary love triangle)
SA: Special A (didn't finish the story, added a lot of filler, weird artwork in the anime)

I would like to see "The Rose of Versailles" remade. I loved it so much when I was a child. I've watched it the first time when I was 5 or 6 years old and I think everybody who watched this series can imagine how I felt at the end, especially because I've never heard of this french revolution before. That's why I still feel happy and incredible sad at the same time when I watch the OP.
I still love the original but it's already 37 years old and I think it's time for a remake.